since the background is bright due to the outdoor light as well as white of the curtains, the subject has been rendered dark. the camera is reading the bright light as well the white, thus underexposing the main subject.

This time the focusing point was overlaped on the subject and then recomposed to get the existing frame. Alternatively the focusing point on the right of the frame could have been selected. the spot metering coincides the focusing point chosen. Besides the right spot metering the exposure is also +1 of the exposure value.

Two things were working against the shot. The bright outside light and the white curtains. For this shot a flash (580exII) on camera was bounced from the white ceiling of the room with the flash card out.